Pre-fALS is a prospective natural history and biomarker study of people not yet affected with ALS, but who are at genetic risk for developing ALS. The investigators aim to recruit unaffected (healthy) people from familial ALS (fALS) pedigrees in which a known genetic mutation associated with ALS has been identified; for this study, a fALS pedigree is one with two biologically related individuals who have or have had ALS and/or FTD. Individuals who may be at genetic risk for ALS and who belong to families with at least one affected family member who has tested positive for a known ALS genetic mutation may also be eligible to participate. Our goal is to study the pre-symptomatic phase, onset and progression of ALS and to learn more about genetic and environmental factors that put people at risk for developing ALS.